package org.apache.maven.model.building;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/**
 * Describes a problem that was encountered during model building. A problem can either be an
 * exception that was thrown or a simple string message. In addition, a problem carries a hint about
 * its source, e.g. the POM file that exhibits the problem.
 * 
 * @author Benjamin Bentmann
 */
public interface ModelProblem {

  /**
   * The different severity levels for a problem, in decreasing order.
   */
  enum Severity {

    FATAL, //
    ERROR, //
    WARNING //

  }

  enum Version {
    // based on ModeBuildingResult.validationLevel
    BASE, V20, V30, V31
  }

  /**
   * Gets the hint about the source of the problem. While the syntax of this hint is unspecified and
   * depends on the creator of the problem, the general expectation is that the hint provides
   * sufficient information to the user to track the problem back to its origin. A concrete example
   * for such a source hint can be the file path or URL from which a POM was read.
   * 
   * @return The hint about the source of the problem or an empty string if unknown, never
   *         {@code null}.
   */
  String getSource();

  /**
   * Gets the one-based index of the line containing the problem. The line number should refer to
   * some text file that is given by {@link #getSource()}.
   * 
   * @return The one-based index of the line containing the problem or a non-positive value if
   *         unknown.
   */
  int getLineNumber();

  /**
   * Gets the one-based index of the column containing the problem. The column number should refer
   * to some text file that is given by {@link #getSource()}.
   * 
   * @return The one-based index of the column containing the problem or non-positive value if
   *         unknown.
   */
  int getColumnNumber();

  /**
   * Gets the identifier of the model from which the problem originated. While the general form of
   * this identifier is <code>groupId:artifactId:version</code> the returned identifier need not be
   * complete. The identifier is derived from the information that is available at the point the
   * problem occurs and as such merely serves as a best effort to provide information to the user to
   * track the problem back to its origin.
   * 
   * @return The identifier of the model from which the problem originated or an empty string if
   *         unknown, never {@code null}.
   */
  String getModelId();

  /**
   * Gets the exception that caused this problem (if any).
   * 
   * @return The exception that caused this problem or {@code null} if not applicable.
   */
  Exception getException();

  /**
   * Gets the message that describes this problem.
   * 
   * @return The message describing this problem, never {@code null}.
   */
  String getMessage();

  /**
   * Gets the severity level of this problem.
   * 
   * @return The severity level of this problem, never {@code null}.
   */
  Severity getSeverity();

  /**
   * Gets the applicable maven version/validation level of this problem
   * 
   * @return The version, never {@code null}.
   */
  Version getVersion();

}
